Multiple-input multiple-output (MIMO) radio communication techniques increase the throughput of a communication system by taking advantage of multiple transmit and multiple receive antennas, which can be generally considered belonging to the class of multi-port antennas. MIMO methods use multi-port antennas having radiation patterns featuring low correlation. Low correlation may be a result of low electrical coupling between antenna ports. Presently, multi-port antenna systems for MIMO are designed by decoupling the antenna ports electrically, which is difficult and poses many geometrical and mechanical constraints, particularly in crowded and electrically small handsets. Antenna port decoupling approaches include separating antenna elements physically, placing antenna elements orthogonal to each other, or by feeding antenna element pairs in an even and odd fashion. However, all of these decoupling approaches place significant constraints on the handset ID, architecture, and mechanics. For instance, even/odd feeding is an effective means of decoupling antenna ports if the device hosting the antenna and the antenna elements feature substantially mirror-like symmetries. Furthermore, near-field coupling with the user's body disrupts symmetries. Additionally, implementing MIMO antenna systems under volume constraints makes it difficult to achieve proper antenna isolation.
Accordingly, there is need to improve the implementation of MIMO antenna systems for use in wireless communication devices.
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The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.